The National Honor Society at Central High School plans to sample a random group of 100 seniors from all high schools in the state in which Central High School is located to determine the average number of hours per week spent on homework. A 95 percent confidence interval for the mean number of hours spent on homework will then be constructed using the sample data. Before selecting the sample, the National Honor Society decides that it wants to decrease the margin of error. Which of the following is the best way to decrease the margin of error?

The New York Times conducted a nationwide poll of 1048 randomly selected 13- to 17-year-olds. to estimate the proportion of 13- to 17-year-olds who have a television in their room. We can consider the sample to be a simple random sample. Of these 1048 teenagers, 692 had a television in their room. Give a 95% confidence interval for the proportion of all people in this age group who had a TV in their room at the time of the poll, and interpret what your interval means in context. State: Plan:  Do: Conclude:

An apartment hunter is shopping for either a one-bedroom or two-bedroom apartment in varying apartment buildings. She wants to estimate the additional amount she would have to pay, on average, for a two-bedroom apartment versus a one-bedroom apartment. The table shows the prices, in dollars, for one- and two-bedroom apartments from the nine buildings she visited.   A 95% confidence interval for the true mean difference between two-bedroom and one-bedroom apartments for apartment buildings like the ones in the sample was (255.93, 508.51). A friend of the apartment hunter tells her to expect to pay about $500 more per month for a two-bedroom apartment than for a one-bedroom apartment. Does the confidence interval provide evidence for the friend’s claim? A. No, the confidence interval does not contain 0, so the friend’s claim is not plausible. B. No, the confidence interval contains many more numbers below 500 than above 500, so it is unlikely that the friend’s assertion is correct. C.…

In a survey of 6000 high school students, 3230 read books during the summer break. Using these sample statistics, find a 99% confidence interval for the proportion p of all high school students that read books during the summer break.

Among 1815 randomly selected high school students surveyed by the Centers for Diseases Control, 300 said they were current smokers. d. Interpret the 95% confidence interval in this context.

Car and Driver Magazine tested a random sample of 9 hybrid cars and found their MPG to be 42, 51, 39, 44, 52, 48, 51, 44, and 47. Construct a 95% confidence interval for the population variance.

A political scientist claims that 38% of first-year college students characterize themselves as being “moderate” or “middle of the road” as far as their political affiliation is concerned.   Believing this claimed value is too high, you survey a random sample of 400 first-year college students and find that 120 characterize themselves as being “moderate” or “middle of the road.”    Based on this information, what will the test statistic be? Choose the answer below that is closest to what you calculate, and try not to do a lot of rounding until you get to the very end of your calculations.   1. -0.3 2. -1.2 3. -2.6 4. -3.3 5. None of the other answer options are correct because the test statistic should be positive, not negative.

A study of 30 college students showed that 25 are binge watching series. Find a 95% confidence interval for the proportion of students that are binge watching series.

An internet study was mailed to 2336 subjects randomly. 1108 surveys were returned. Construct a 95% confidence interval for the proportion of the returned surveys. identify the margin of error E.

A recent survey of 1,000 people found that 90% of Americans support background checks for purchasing guns. Construct a 95 % confidence interval for the population proportion.